Wireless video endoscopy or video capsule endoscopy (VCE) is a noninvasive technology designed primarily to provide diagnostic imaging of the small intestine, an anatomic site that has proven peculiarly difficult to visualize. Limited views of the esophagus, stomach, and cecum may also be acquired. Images acquired are of excellent resolution and have a 1:8 magnification, which is higher than that of conventional endoscopes. This magnification allows visualization of individual villi. VCE approaches the concept of physiological endoscopy since the capsule moves passively, does not inflate the bowel, and images the mucosa in the collapsed state. More recently, double-ended wireless video capsules have been developed for the examination of the esophagus and colon.
This topic will review the use of wireless video capsule endoscopy for evaluation of the esophagus, small bowel and the colon. The approaches to patients with occult and/or obscure gastrointestinal bleeding are discussed in detail elsewhere. (See "Evaluation of occult gastrointestinal bleeding" and "Evaluation of obscure gastrointestinal bleeding".)
There are three small bowel capsules (PillCam SB, EndoCapsule, and MiRo capsule) and one esophageal capsule (PillCam ESO) that are available. A colonic capsule is also available in Europe, the United States, and Japan (PillCam Colon). (See 'Colon capsule endoscopy' below.)
The US Food and Drug Administration (FDA) approved the original capsule (Given Imaging, Ltd, Yoqneam, Israel) in August 2001 [1,2]. It was subsequently replaced by the M2A Plus capsule, which has now been renamed the PillCam (PillCam SB). The PillCam is now in its third generation (PillCam SB3). This version has an improved resolution and a variable frame rate. The frame rate increases to six frames per second when it is moving quickly, as in the duodenal sweep, and slows to two frames per second when moving slowly or when stationary. It has a "suspected blood indicator," which may facilitate identification of bleeding sites, although the clinical value of this feature is unclear since the sensitivity and specificity are poor [3-5]. The latest version of the PillCam software has discontinued the ability to track the location of the capsule within the abdominal cavity because of poor accuracy.
In October 2007, the FDA approved a second small bowel capsule (EndoCapsule, Olympus Corporation, Allentown, PA). It has similar characteristics to the PillCam SB but has a charge-coupled device (CCD) chip instead of a complementary metal-oxide-semiconductor (CMOS) chip. FDA approval was based upon a study of 51 patients with obscure gastrointestinal bleeding who swallowed both the PillCam SB and the EndoCapsule 40 minutes apart in randomized order . The devices were similar, based upon the detection of normal versus abnormal and in diagnostic capability. This study also demonstrated that a capsule does not always travel axially, but may tumble. Furthermore, non-axial movement implies incomplete mucosal visualization, one of the limitations of the technology. The original EndoCapsule has been superseded by the EndoCapsule 10, which has also received FDA approval. This device has increased resolution and 3D location software.